File download issue with Sitecore MVC and resolution


The problem:

while working on the requirement of downloading calendar item(.ics) for an event on the site, I struck with the below given error.

OutputStream is not available when a custom TextWriter is used.

OutputStream is not available when a custom TextWriter is used.
Sitecore MVC error for File as ActionResult for post action

 

Steps to reproduce issue/problem

  1. Using Sitecore MVC form to do the form posting
 @using (Html.BeginRouteForm(Sitecore.Mvc.Configuration.MvcSettings.SitecoreRouteName, FormMethod.Post))
 {
     @Html.Sitecore().FormHandler("SeminarWebinarEvent", "DownloadCalendar")
     @Html.Hidden("eventId", @eventObj.Id.ToString())
     <button type="submit">Add to Calender</button>
 }
  1. Controller Post Action
 [HttpPost]
 public ActionResult DownloadCalendar(string eventId)
 {
     var eventItem = Sitecore.Context.Database.GetItem(new ID(eventId));
     if (eventItem == null)
     {
         //// TODO : Put the code for the error handling
     }

     //// get file stream
     var fileStream = this.eventService.GetCalendarFileStream(eventItem);
     return File(fileStream , "text/calendar", string.Format("{0}.ics", eventItem.Name));
 }
  1. Finally, Click on the Download link of the rendering on the page.

Root Cause

For the fix and the root cause I took the help of the God (not the real almighty but Google ;-)). I found that because of the basic page architecture of Sitecore, the page rendering has already started before the rendering control action returns the file response.

Solution :

After applying couple of different solutions(every time with fingers crossed), I found below given solution much handy and does the job. The solution is much simple and easy to implement.
In this case we need to split the whole action into two different actions like shown in below steps.

  1. Step 1

Put the logic of creating file stream in one action

 [HttpPost]
 public ActionResult DownloadCalendar(string eventId)
     {
          var eventItem = Sitecore.Context.Database.GetItem(new ID(eventId));
          if (eventItem == null)
          {
              //// TODO : Put the code for the error handling
          }

          //// read the file stream in the string format
          var fileStream = this.eventService.GetCalendarFileStream(eventItem);
          //// due to limitation of sitecore MVC redirect to the different action which is responsible for actual download
          return RedirectToAction("ActualCalenderDownload", new { fileString = fileStream, fileName = eventItem["Name"] });
        }
  1. Step 2

At the end of the action redirect to another action which is actually responsible for downloading the file.

  1. Step 3

Create the new action which takes the file stream from above action and returns the fileResult

 [HttpGet]
 public ActionResult ActualCalenderDownload(string fileString, string fileName)
 {
      if (string.IsNullOrWhiteSpace(fileString))
      {
          //// TODO : Put the code for the error handling
      }

      return File(Encoding.UTF8.GetBytes(fileString), "text/calendar", string.Format("{0}.ics", fileName));
 }

Happy Coding 🙂

Sitecore controller rendering action results – what can I return?

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Sitecore 7.2 MVC with MVC 5


The problem:

Make the MVC 5.2 code working on Sitecore .NET 7.2 (rev. 140526) using VS 2013 Update 3

Steps to reproduce issue/problem
1. Setup Sitecore.NET 7.2 (rev. 140526) with default MVC configuration, As MVC is default enabled as mentioned in document from Sitecore at http://sdn.sitecore.net/upload/sitecore7/72/installation_guide_sc72-a4.pdf,

2. Create new View in VS 2013 Update 3, With default “ASP.Net Web Application” project template.

3. Configure publishing to do the deployment to local file system.

4. publish Project to Web Directory

5. it will produce following error



Server Error in '/' Application.
Could not load file or assembly 'System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.IO.FileLoadException: Could not load file or assembly 'System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Assembly Load Trace: The following information can be helpful to determine why the assembly 'System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Stack Trace:

[FileLoadException: Could not load file or assembly 'System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
Sitecore.Mvc.Pipelines.Loader.InitializeGlobalFilters.AddGlobalFilters(PipelineArgs args) +0
(Object , Object[] ) +83
Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +365
Sitecore.Nexus.Web.HttpModule.Application_Start() +172
Sitecore.Nexus.Web.HttpModule.Init(HttpApplication app) +516
System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +530
System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +304
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +404
System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +475

[HttpException (0x80004005): Could not load file or assembly 'System.Web.Mvc, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +12601936
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +159
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +12441597

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34009


Solution :

1. Open the Web.config
2. Navigate to the “configuration\runtime\assemblyBinding\dependentAssembly” and search for below given configuration lines

<dependentAssembly>
    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" xmlns="urn:schemas-microsoft-com:asm.v1" />
    <bindingRedirect oldVersion="1.0.0.0-5.2.0.0" newVersion="5.2.0.0" xmlns="urn:schemas-microsoft-com:asm.v1" />
</dependentAssembly>

3. Replace the olderVersion value to “1.0.0.0-5.2.0.0” (this does the trick)

4. change the version of the new assembly i.e. newVersion value to “5.2.0.0”

As a good practice you may also need to update assembly version number at “system.web\compilation\assemblies” for the System.Web.Mvc